/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/

function p(value, timeout = 10) {
	return new Promise(resolve => {
		setTimeout(() => {
			resolve(value)
		}, timeout)
	})
}

p('hello')
	.then(val => p(val + ' lagou'))
	.then(val => p(val + ' I ♥ U'))
	.then(console.log)
